Patterned application of activated carbon ink

ABSTRACT

An odor control substrate that is applied with an activated carbon ink is provided. The activated carbon ink is applied in a pattern that covers from about 25% to about 95% of the surface area of the substrate. Although not covering the entire surface, the present inventors have discovered that the activated carbon ink is still capable of providing good odor reduction qualities to the substrate. To further enhance the aesthetic appeal of the odor control substrate to a consumer, one or more colored inks may also be applied the substrate in a pattern that may or may not overlap with the activated carbon ink pattern. The colored ink(s) may contrast well with the activated carbon ink to provide an overall design that is more aesthetically than otherwise would be provided by a uniform coating of activated carbon ink.

BACKGROUND OF THE INVENTION

Odor control additives have been conventionally incorporated intosubstrates for a variety of reasons. For instance, absorbent articlesmay contain odor control additives to absorb compounds that result inthe production of malodors contained in absorbed fluids or theirdegradation products. Examples of these compounds include fatty acids,ammonia, amines, sulfur-containing compounds, ketones and aldehydes.Various types of odor control additives have been employed for thispurpose. For instance, activated carbon has been used to reduce a broadspectrum of odors. In spite of its excellent properties as an adsorbent,the use of activated carbon in disposable absorbent articles has beenlimited by its black color. That is, many consumers associate thetraditionally black color of activated carbon with a dirty or grimymaterial.

As such, a need currently exists for odor control substrates that arecapable of achieving reducing odor, and yet also aesthetically pleasingto a consumer.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a method forforming an odor control substrate is disclosed. The method comprisesforming a first ink that comprises activated carbon, a binder, and asolvent. The first ink is printed onto a surface of the substrate sothat it covers from about 25% to about 95% of the area of the surface.The first ink is dried and has a solids add-on level of at least about2%. The first ink also presents a color (e.g., black) that is visuallydistinguishable from another color presented by the substrate. Ifdesired, a second ink may also be printed onto the substrate thatpresents a color that is visually distinguishable from the color of thefirst ink. For example, the color of the second ink may be white,yellow, cyan, magenta, red, green, blue, or combinations thereof. Thefirst and second inks may be applied in an overlapping and/ornon-overlapping relationship.

In accordance with another embodiment of the present invention, an odorcontrol substrate is disclosed that is applied with a first ink and asecond ink, the first ink comprising activated carbon. The first inkcovers from about 30% to about 90% of the area of a surface of thesubstrate and is present at a solids add-on level of at least about 2%.The first ink presents a color that is visually distinguishable from thecolor of the second ink.

In accordance with still another embodiment of the present invention, apouch for individually wrapping a feminine care absorbent article isdisclosed. The pouch comprises a wrapper having an inner surface. Theinner surface is applied with a first ink that comprises activatedcarbon. The first ink covers from about 25% to about 95% of the area ofthe inner surface. The first ink presents a color that is visuallydistinguishable from another color presented by the wrapper.

Other features and aspects of the present invention are described inmore detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth more particularly in the remainder of the specification, whichmakes reference to the appended figures in which:

FIG. 1 illustrates an odor control substrate having overlapping colorpatterns in accordance with one embodiment of the present invention, inwhich FIG. 1A depicts a colored ink printed on top of an activatedcarbon ink and in which FIG. 1B depicts an activated carbon ink printedon top of a colored ink;

FIG. 2 illustrates an odor control substrate having non-overlappingcolor patterns in accordance with another embodiment of the presentinvention;

FIG. 3 is a perspective view of one embodiment of an individuallywrapped absorbent article package of the present invention;

FIG. 4 is a perspective view of the package of FIG. 1 shown in itsopened state; and

FIG. 5 graphically depicts the results of the Example 1, in which theodor adsorption of ethyl mercaptan is plotted versus coverage area forvarious coating weights.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF THE REPRESENTATIVE EMBODIMENTS Definitions

As used herein the term “nonwoven fabric or web” refers to a web havinga structure of individual fibers or threads which are interlaid, but notin an identifiable manner as in a knitted fabric. Nonwoven fabrics orwebs have been formed from many processes such as for example,meltblowing processes, spunbonding processes, bonded carded webprocesses, etc.

As used herein, the term “meltblown web” generally refers to a nonwovenweb that is formed by a process in which a molten thermoplastic materialis extruded through a plurality of fine, usually circular, diecapillaries as molten fibers into converging high velocity gas (e.g.air) streams that attenuate the fibers of molten thermoplastic materialto reduce their diameter, which may be to microfiber diameter.Thereafter, the meltblown fibers are carried by the high velocity gasstream and are deposited on a collecting surface to form a web ofrandomly disbursed meltblown fibers. Such a process is disclosed, forexample, in U.S. Pat. No. 3,849,241 to Butin, et al., which isincorporated herein in its entirety by reference thereto for allpurposes. Generally speaking, meltblown fibers may be microfibers thatare substantially continuous or discontinuous, generally smaller than 10microns in diameter, and generally tacky when deposited onto acollecting surface.

As used herein, the term “spunbond web” generally refers to a webcontaining small diameter substantially continuous fibers. The fibersare formed by extruding a molten thermoplastic material from a pluralityof fine, usually circular, capillaries of a spinnerette with thediameter of the extruded fibers then being rapidly reduced as by, forexample, eductive drawing and/or other well-known spunbondingmechanisms. The production of spunbond webs is described andillustrated, for example, in U.S. Pat. No. 4,340,563 to Appel, et al.,U.S. Pat. No. 3,692,618 to Dorschner, et al., U.S. Pat. No. 3,802,817 toMatsuki, et al., U.S. Pat. No. 3,338,992 to Kinney, U.S. Pat. No.3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, U.S. Pat. No.3,502,538 to Levy, U.S. Pat. No. 3,542,615 to Dobo, et al., and U.S.Pat. No. 5,382,400 to Pike, et al., which are incorporated herein intheir entirety by reference thereto for all purposes. Spunbond fibersare generally not tacky when they are deposited onto a collectingsurface. Spunbond fibers may sometimes have diameters less than about 40microns, and are often between about 5 to about 20 microns.

As used herein, the term “coform” generally refers to compositematerials comprising a mixture or stabilized matrix of thermoplasticfibers and a second non-thermoplastic material. As an example, coformmaterials may be made by a process in which at least one meltblown diehead is arranged near a chute through which other materials are added tothe web while it is forming. Such other materials may include, but arenot limited to, fibrous organic materials such as woody or non-woodypulp such as cotton, rayon, recycled paper, pulp fluff and alsosuperabsorbent particles, inorganic and/or organic absorbent materials,treated polymeric staple fibers and so forth. Some examples of suchcoform materials are disclosed in U.S. Pat. No. 4,100,324 to Anderson,et al.; U.S. Pat. No. 5,284,703 to Everhart, et al.; and U.S. Pat. No.5,350,624 to Georger, et al.; which are incorporated herein in theirentirety by reference thereto for all purposes.

As used herein, the term “multicomponent fibers” generally refers tofibers that have been formed from at least two polymer components. Suchfibers are typically extruded from separate extruders, but spun togetherto form one fiber. The polymers of the respective components aretypically different, but may also include separate components of similaror identical polymeric materials. The individual components aretypically arranged in substantially constantly positioned distinct zonesacross the cross-section of the fiber and extend substantially along theentire length of the fiber. The configuration of such fibers may be, forexample, a side-by-side arrangement, a pie arrangement, or any otherarrangement. Multicomponent fibers and methods of making the same aretaught in U.S. Pat. No. 5,108,820 to Kaneko, et al., U.S. Pat. No.4,795,668 to Kruege. et al., U.S. Pat. No. 5,382,400 to Pike, et al.,U.S. Pat. No. 5,336,552 to Strack, et al., and U.S. Pat. No. 6,200,669to Marmon, et al., which are incorporated herein in their entirety byreference thereto for all purposes. The fibers and individual componentscontaining the same may also have various irregular shapes such as thosedescribed in U.S. Pat. No. 5,277,976 to Hogle, et al., U.S. Pat. No.5,162,074 to Hills, U.S. Pat. No. 5,466,410 to Hills, U.S. Pat. No.5,069,970 to Largman, et al., and U.S. Pat. No. 5,057,368 to Larqman, etal., which are incorporated herein in their entirety by referencethereto for all purposes.

As used herein, the term “elastomeric” and “elastic” and refers to amaterial that, upon application of a stretching force, is stretchable inat least one direction (such as the CD direction), and which uponrelease of the stretching force, contracts/returns to approximately itsoriginal dimension. For example, a stretched material may have astretched length that is at least 50% greater than its relaxedunstretched length, and which will recover to within at least 50% of itsstretched length upon release of the stretching force. A hypotheticalexample would be a one (1) inch sample of a material that is stretchableto at least 1.50 inches and which, upon release of the stretching force,will recover to a length of not more than 1.25 inches. Desirably, suchelastomeric sheet contracts or recovers at least 50%, and even moredesirably, at least 80% of the stretch length in the cross machinedirection.

As used herein, the term “breathable” means pervious to water vapor andgases, but impermeable to liquid water. For instance, “breathablebarriers” and “breathable films” allow water vapor to pass therethrough,but are substantially impervious to liquid water. The “breathability” ofa material is measured in terms of water vapor transmission rate (WVTR),with higher values representing a more vapor-pervious material and lowervalues representing a less vapor-pervious material. Typically, the“breathable” materials have a water vapor transmission rate (WVTR) offrom about 500 to about 20,000 grams per square meter per 24 hours(g/m²/24 hours), in some embodiments from about 1,000 to about 15,000g/m²/24 hours, and in some embodiments, from about 1,500 to about 14,000g/m²/24 hours.

As used herein, an “absorbent article” refers to any article capable ofabsorbing water or other fluids. Examples of some absorbent articlesinclude, but are not limited to, personal care absorbent articles, suchas diapers, training pants, absorbent underpants, adult incontinenceproducts, feminine hygiene products (e.g., sanitary napkins), swim wear,baby wipes, and so forth; medical absorbent articles, such as garments,fenestration materials, underpads, bandages, absorbent drapes, andmedical wipes; food service wipers; clothing articles; and so forth.Materials and processes suitable for forming such absorbent articles arewell known to those skilled in the art.

DETAILED DESCRIPTION

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation, not limitation of theinvention. In fact, it will be apparent to those skilled in the art thatvarious modifications and variations may be made in the presentinvention without departing from the scope or spirit of the invention.For instance, features illustrated or described as part of oneembodiment, may be used on another embodiment to yield a still furtherembodiment. Thus, it is intended that the present invention cover suchmodifications and variations.

In general, the present invention is directed to an odor controlsubstrate that is applied with an activated carbon ink. The activatedcarbon ink is applied in a pattern that covers from about 25% to about95% of the surface area of the substrate. Although not covering theentire surface, the present inventors have discovered that the activatedcarbon ink is still capable of providing good odor reduction qualitiesto the substrate. To further enhance the aesthetic appeal of the odorcontrol substrate to a consumer, one or more colored inks may also beapplied the substrate in a pattern that may or may not overlap with theactivated carbon ink pattern. The colored ink(s) may contrast well withthe activated carbon ink to provide an overall design that is moreaesthetically than otherwise would be provided by a uniform coating ofactivated carbon ink.

A. Substrates

Any of variety of substrates may be applied with an activated carbon inkin accordance with the present invention. For example, nonwoven webs,woven fabrics, knit fabrics, films, and so forth, may be employed. Inmost embodiments, the substrate contains at least one nonwoven web. Whenutilized, the nonwoven web may include, but not limited to, spunbondwebs, meltblown webs, bonded carded webs, air-laid webs, coform webs,hydraulically entangled webs, and so forth. Nonwoven webs may be formedby a variety of different materials. For instance, suitable polymers forforming nonwoven webs may include polyolefins, polyamides, polyesters,polycarbonates, polystyrenes, thermoplastic elastomers, fluoropolymers,vinyl polymers, and blends and copolymers thereof. Suitable polyolefinsinclude, but are not limited to, polyethylene, polypropylene,polybutylene, and so forth; suitable polyamides include, but are notlimited to, nylon 6, nylon 6/6, nylon 10, nylon 12 and so forth; andsuitable polyesters include, but are not limited to, polyethyleneterephthalate, polybutylene terephthalate, polytrimethyl terephthalate,polylactic acid, and so forth. Particularly suitable polymers for use inthe present invention are polyolefins including polyethylene, forexample, linear low density polyethylene, low density polyethylene,medium density polyethylene, and high density polyethylene;polypropylene; polybutylene; as well as copolymers and blends thereof.

The fibers used to form the nonwoven web may be in the form ofsubstantially continuous fibers, staple fibers, and so forth.Substantially continuous fibers, for example, may be produced by knownnonwoven extrusion processes, such as, for example, known solventspinning or melt-spinning processes. In one embodiment, the nonwoven webcontains substantially continuous melt-spun fibers formed by a spunbondprocess. The spunbond fibers may be formed from any melt-spinnablepolymer, co-polymers or blends thereof. The denier of the fibers used toform the nonwoven web may also vary. For instance, in one particularembodiment, the denier of polyolefin fibers used to form the nonwovenweb is less than about 6, in some embodiments less than about 3, and insome embodiments, from about 1 to about 3. In one particular embodimentof the present invention, multicomponent (e.g., bicomponent) fibers areutilized. For example, suitable configurations for the multicomponentfibers include side-by-side configurations and sheath-coreconfigurations, and suitable sheath-core configurations includeeccentric sheath-core and concentric sheath-core configurations. In someembodiments, as is well known in the art, the polymers used to form themulticomponent fibers have sufficiently different melting points to formdifferent crystallization and/or solidification properties. Themulticomponent fibers may have from about 20% to about 80%, and in someembodiments, from about 40% to about 60% by weight of the low meltingpolymer. Further, the multicomponent fibers may have from about 80% toabout 20%, and in some embodiments, from about 60% to about 40%, byweight of the high melting polymer.

As stated above, a film may also be utilized to form the substrate. Toform a film, a variety of materials may be utilized. For instance, somesuitable thermoplastic polymers used in the fabrication of films mayinclude, but are not limited to, polyolefins (e.g., polyethylene,polypropylene, etc.), including homopolymers, copolymers, terpolymersand blends thereof; ethylene vinyl acetate; ethylene ethyl acrylate;ethylene acrylic acid; ethylene methyl acrylate; ethylene normal butylacrylate; polyurethane; poly(ether-ester); poly(amid-ether) blockcopolymers; and so forth.

In one particular embodiment, the film may be made a liquid-impermeableplastic film, such as a polyethylene and polypropylene film. Generally,such plastic films are impermeable to gases and water vapor, as well asliquids. In addition, the film may be impermeable to liquids, butpermeable to gases and water vapor (i.e., “breathable”). Such breathablefilms are useful in a variety of articles, such as in an outer cover ofan absorbent article to permit vapors to escape from the absorbent core,but prevent liquid exudates from passing therethrough. The breathablefilm may be microporous or monolithic. In microporous films, themicropores form what is often referred to as tortuous pathways throughthe film. Liquid contacting one side of the film does not have a directpassage through the film. Instead, a network of microporous channels inthe film prevents liquids from passing, but allows gases and water vaporto pass. Microporous films may be formed from a polymer and a filler(e.g., calcium carbonate). Fillers are particulates or other forms ofmaterial that may be added to the film polymer extrusion blend and thatwill not chemically interfere with the extruded film, but which may beuniformly dispersed throughout the film. Generally, on a dry weightbasis, based on the total weight of the film, the film includes fromabout 30% to about 90% by weight of a polymer. In some embodiments, thefilm includes from about 30% to about 90% by weight of a filler.Examples of such films are described in U.S. Pat. No. 5,843,057 toMcCormack; U.S. Pat. No. 5,855,999 to McCormack; U.S. Pat. No. 5,932,497to Morman. et al.; U.S. Pat. No. 5,997,981 to McCormack et al.; U.S.Pat. No. 6,002,064 to Kobvlivker, et al.; U.S. Pat. No. 6,015,764 toMcCormack, et al.; U.S. Pat. No. 6,037,281 to Mathis, et al.; U.S. Pat.No. 6,111,163 to McCormack, et al.; and U.S. Pat. No. 6,461,457 toTaylor, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

The films are generally made breathable by stretching the filled filmsto create the microporous passageways as the polymer breaks away fromthe calcium carbonate during stretching. For example, the breathablematerial contains a stretch-thinned film that includes at least twobasic components, i.e., a polyolefin polymer and filler. Thesecomponents are mixed together, heated, and then extruded into a filmlayer using any one of a variety of film-producing processes known tothose of ordinary skill in the film processing art. Such film-makingprocesses include, for example, cast embossed, chill and flat cast, andblown film processes.

Another type of breathable film is a monolithic film that is anonporous, continuous film, which because of its molecular structure, iscapable of forming a liquid-impermeable, vapor-permeable barrier. Amongthe various polymeric films that fall into this type include films madefrom a sufficient amount of poly(vinyl alcohol), polyvinyl acetate,ethylene vinyl alcohol, polyurethane, ethylene methyl acrylate, andethylene methyl acrylic acid to make them breathable. Without intendingto be held to a particular mechanism of operation, it is believed thatfilms made from such polymers solubilize water molecules and allowtransportation of those molecules from one surface of the film to theother. Accordingly, these films may be sufficiently continuous, i.e.,nonporous, to make them substantially liquid-impermeable, but stillallow for vapor permeability.

Breathable films, such as described above, may constitute the entirebreathable material, or may be part of a multilayer film. Multilayerfilms may be prepared by cast or blown film coextrusion of the layers,by extrusion coating, or by any conventional layering process. Further,other breathable materials that may be suitable for use in the presentinvention are described in U.S. Pat. No. 4,341,216 to Obenour; U.S. Pat.No. 4,758,239 to Yeo, et al.; U.S. Pat. No. 5,628,737 to Dobrin, et al.;U.S. Pat. No. 5,836,932 to Buell; U.S. Pat. No. 6,114,024 to Forte; U.S.Pat. No. 6,153,209 to Vega, et al.; U.S. Pat. No. 6,198,018 to Curro;U.S. Pat. No. 6,203,810 to Alemany, et al.; and U.S. Pat. No. 6,245,401to Ying, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

If desired, the breathable film may also be bonded to a nonwoven web,knitted fabric, and/or woven fabric using well-known techniques. Forinstance, suitable techniques for bonding a film to a nonwoven web aredescribed in U.S. Pat. No. 5,843,057 to McCormack; U.S. Pat. No.5,855,999 to McCormack; U.S. Pat. No. 6,002,064 to Kobylivker, et al.;U.S. Pat. No. 6,037,281 to Mathis, et al.; and WO 99/12734, which areincorporated herein in their entirety by reference thereto for allpurposes. For example, a breathable film/nonwoven laminate material maybe formed from a nonwoven layer and a breathable film layer. The layersmay be arranged so that the breathable film layer is attached to thenonwoven layer. In one particular embodiment, the breathable material isformed from a nonwoven fabric (e.g., polypropylene spunbond web)laminated to a breathable film.

The substrate may also contain an elastomeric polymer, such aselastomeric polyesters, elastomeric polyurethanes, elastomericpolyamides, elastomeric polyolefins, elastomeric copolymers, and soforth. Examples of elastomeric copolymers include block copolymershaving the general formula A-B-A′ or A-B, wherein A and A′ are each athermoplastic polymer endblock that contains a styrenic moiety and B isan elastomeric polymer midblock, such as a conjugated diene or a loweralkene polymer. Such copolymers may include, for instance,styrene-isoprene-styrene (S-I-S), styrene-butadiene-styrene (S-B-S),styrene-ethylene-butylene-styrene (S-EB-S), styrene-isoprene (S-I),styrene-butadiene (S-B), and so forth. Commercially available A-B-A′ andA-B-A-B copolymers include several different S-EB-S formulations fromKraton Polymers of Houston, Tex. under the trade designation KRATON®.KRATON® block copolymers are available in several differentformulations, a number of which are identified in U.S. Pat. Nos.4,663,220, 4,323,534, 4,834,738, 5,093,422 and 5,304,599, which arehereby incorporated in their entirety by reference thereto for allpurposes. Other commercially available block copolymers include theS-EP-S elastomeric copolymers available from Kuraray Company, Ltd. ofOkayama, Japan, under the trade designation SEPTON®. Still othersuitable copolymers include the S-I-S and S-B-S elastomeric copolymersavailable from Dexco Polymers of Houston, Tex. under the tradedesignation VECTOR®. Also suitable are polymers composed of an A-B-A-Btetrablock copolymer, such as discussed in U.S. Pat. No. 5,332,613 toTaylor, et al., which is incorporated herein in its entirety byreference thereto for all purposes. An example of such a tetrablockcopolymer is astyrene-poly(ethylene-propylene)-styrene-poly(ethylene-propylene)(“S-EP-S-EP”) block copolymer.

Examples of elastomeric polyolefins include ultra-low densityelastomeric polypropylenes and polyethylenes, such as those produced by“single-site” or “metallocene” catalysis methods. Such elastomericolefin polymers are commercially available from ExxonMobil Chemical Co.of Houston, Tex. under the trade designations ACHIEVE®(propylene-based), EXACT® (ethylene-based), and EXCEED®(ethylene-based). Elastomeric olefin polymers are also commerciallyavailable from DuPont Dow Elastomers, LLC (a joint venture betweenDuPont and the Dow Chemical Co.) under the trade designation ENGAGE®(ethylene-based) and from Dow Chemical Co. of Midland, Mich. under thename AFFINITY® (ethylene-based). Examples of such polymers are alsodescribed in U.S. Pat. Nos. 5,278,272 and 5,272,236 to Lai, et al.,which are incorporated herein in their entirety by reference thereto forall purposes. Also useful are certain elastomeric polypropylenes, suchas described in U.S. Pat. No. 5,539,056 to Yanq, et al. and U.S. Pat.No. 5,596,052 to Resconi, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

If desired, blends of two or more polymers may also be utilized. Forexample, a blend of a high performance elastomer and a lower performanceelastomer may be utilized. A high performance elastomer is generally anelastomer having a low level of hysteresis, such as less than about 75%,and in some embodiments, less than about 60%. Likewise, a lowperformance elastomer is generally an elastomer having a high level ofhysteresis, such as greater than about 75%. Particularly suitable highperformance elastomers may include styrenic-based block copolymers, suchas described above and commercially available from Kraton Polymers underthe trade designation KRATON® and from Dexco Polymers under the tradedesignation VECTOR®. Likewise, particularly suitable low performanceelastomers include elastomeric polyolefins, such asmetallocene-catalyzed polyolefins (e.g., single sitemetallocene-catalyzed linear low density polyethylene) commerciallyavailable from Dow Chemical Co. under the trade designation AFFINITY®.In some embodiments, the high performance elastomer may constitute fromabout 25 wt. % to about 90 wt. % of the blend, and the low performanceelastomer may likewise constitute from about 10 wt. % to about 75 wt. %of the blend. Further examples of such a high performance/lowperformance elastomer blend are described in U.S. Pat. No. 6,794,024 toWalton, et al., which is incorporated herein in its entirety byreference thereto for all purposes.

B. Activated Carbon Inks

Regardless of the particular substrate selected, an activated carbon inkis applied to the substrate for reducing odor. When applied inaccordance with the present invention, the ink is also durable andpresent in an aesthetically pleasing pattern on the substrate. Generallyspeaking, activated carbon may be derived from a variety of sources,such as from sawdust, wood, charcoal, peat, lignite, bituminous coal,coconut shells, etc. Some suitable forms of activated carbon andtechniques for formation thereof are described in U.S. Pat. No.5,693,385 to Parks; U.S. Pat. No. 5,834,114 to Economy, et al.; U.S.Pat. No. 6,517,906 to Economy, et al.; U.S. Pat. No. 6,573,212 toMcCrae, et al., as well as U.S. Patent Application Publication Nos.2002/0141961 to Falat. et al. and 2004/0166248 to Hu, et al., all ofwhich are incorporated herein in their entirety by reference thereto forall purposes. The concentration of activated carbon in the ink (prior todrying) is generally tailored to facilitate odor control withoutadversely affecting other properties of the substrate, such asflexibility, absorbency, etc. For instance, activated carbon istypically present in the ink in an amount from about 1 wt. % to about 50wt. %, in some embodiments from about 5 wt. % to about 25 wt. %, and insome embodiments, from about 10 wt. % to about 20 wt. %.

The activated carbon ink also generally contains a binder for increasingthe durability of the activated carbon when applied to a substrate, evenwhen present at high levels. The binder may also serve as an adhesivefor bonding one substrate to another substrate. Generally speaking, anyof a variety of binders may be used in the activated carbon ink of thepresent invention. Suitable binders may include, for instance, thosethat become insoluble in water upon crosslinking. Crosslinking may beachieved in a variety of ways, including by reaction of the binder witha polyfunctional crosslinking agent. Examples of such crosslinkingagents include, but are not limited to, dimethylol ureamelamine-formaldehyde, urea-formaldehyde, polyamide epichlorohydrin,etc.

In some embodiments, a polymer latex may be employed as the binder. Thepolymer suitable for use in the lattices typically has a glasstransition temperature of about 30° C. or less so that the flexibilityof the resulting substrate is not substantially restricted. Moreover,the polymer also typically has a glass transition temperature of about−25° C. or more to minimize the tackiness of the polymer latex. Forinstance, in some embodiments, the polymer has a glass transitiontemperature from about −15° C. to about 15° C., and in some embodiments,from about −10° C. to about 0° C. For instance, some suitable polymerlattices that may be utilized in the present invention may be based onpolymers such as, but are not limited to, styrene-butadiene copolymers,polyvinyl acetate homopolymers, vinyl-acetate ethylene copolymers,vinyl-acetate acrylic copolymers, ethylene-vinyl chloride copolymers,ethylene-vinyl chloride-vinyl acetate terpolymers, acrylic polyvinylchloride polymers, acrylic polymers, nitrile polymers, and any othersuitable anionic polymer latex polymers known in the art. The charge ofthe polymer lattices described above may be readily varied, as is wellknown in the art, by utilizing a stabilizing agent having the desiredcharge during preparation of the polymer latex. For instance, specifictechniques for an activated carbon/polymer latex system are described inmore detail in U.S. Pat. No. 6,573,212 to McCrae, et al. Commerciallyavailable activated carbon/polymer latex systems that may be used in thepresent invention include Nuchar® PMA, DPX-8433-68A, and DPX-8433-68B,all of which are available from MeadWestvaco Corp of Covington, Va.

Although polymer lattices may be effectively used as binders in thepresent invention, such compounds sometimes result in a reduction indrapability and an increase in residual odor. Thus, water-solubleorganic polymers may also be employed as binders to alleviate suchconcerns. Another benefit of the water-soluble binder of the presentinvention is that it may facilitate the controlled release of theactivated carbon ink from the substrate in an aqueous environment.Specifically, upon contacting an aqueous solution, the water-solublebinder dissolves and loses some of its binding qualities, therebyallowing other components of the activated carbon ink to be releasedfrom the substrate. This may be useful in various applications, such asfor hard-surface wipers in which it is desired for the activated carbonink to be released into the wiped environment for sustained odorcontrol.

One class of water-soluble organic polymers found to be suitable in thepresent invention is polysaccharides and derivatives thereof.Polysaccharides are polymers containing repeated carbohydrate units,which may be cationic, anionic, nonionic, and/or amphoteric. In oneparticular embodiment, the polysaccharide is a nonionic, cationic,anionic, and/or amphoteric cellulosic ether. Suitable nonioniccellulosic ethers may include, but are not limited to, alkyl celluloseethers, such as methyl cellulose and ethyl cellulose; hydroxyalkylcellulose ethers, such as hydroxyethyl cellulose, hydroxypropylcellulose, hydroxypropyl hydroxybutyl cellulose, hydroxyethylhydroxypropyl cellulose, hydroxyethyl hydroxybutyl cellulose andhydroxyethyl hydroxypropyl hydroxybutyl cellulose; alkyl hydroxyalkylcellulose ethers, such as methyl hydroxyethyl cellulose, methylhydroxypropyl cellulose, ethyl hydroxyethyl cellulose, ethylhydroxypropyl cellulose, methyl ethyl hydroxyethyl cellulose and methylethyl hydroxypropyl cellulose; and so forth.

Suitable cellulosic ethers may include, for instance, those availablefrom Akzo Nobel of Covington, Virginia under the name “BERMOCOLL.” Stillother suitable cellulosic ethers are those available from Shin-EtsuChemical Co., Ltd. of Tokyo, Japan under the name “METOLOSE”, includingMETOLOSE Type SM (methycellulose), METOLOSE Type SH (hydroxypropylmethylcellulose), and METOLOSE Type SE (hydroxyethylmethyl cellulose). Oneparticular example of a suitable nonionic cellulosic ether is ethylhydroxyethyl cellulose having a degree of ethyl substitution (DS) of 0.8to 1.3 and a molar substitution (MS) of hydroxyethyl of 1.9 to 2.9. Thedegree of ethyl substitution represents the average number of hydroxylgroups present on each anhydroglucose unit that have been reacted, whichmay vary between 0 and 3. The molar substitution represents the averagenumber of hydroxethyl groups that have reacted with each anhydroglucoseunit. One such cellulosic ether is BERMOCOLL E 230FQ, which is an ethylhydroxyethyl cellulose commercially available from Akzo Nobel. Othersuitable cellulosic ethers are also available from Hercules, Inc. ofWilmington, Del. under the name “CULMINAL.”

The total concentration of the binders may generally vary depending onthe desired properties of the resulting substrate. For instance, hightotal binder concentrations may provide better physical properties forthe coated substrate, but may likewise have an adverse affect on otherproperties, such as the absorptive capacity or extensibility of thesubstrate to which it is applied. Conversely, low total binderconcentrations may not provide the desired degree of durability. Thus,in most embodiments, the total amount of binder employed in theactivated carbon ink (prior to drying) is from about 0.01 wt. % to about30 wt. %, in some embodiments from about 0.1 wt. % to about 20 wt. %,and in some embodiments, from about 1 wt. % to about 15 wt. %.

Besides the above-mentioned components, a masking agent may also beemployed in the activated carbon ink to further alter the aestheticproperties of the substrate. That is, the masking agent may enhanceopacity and/or alter the color to the ink. To provide optimum maskingeffects, the size of the particles is desirably less than the size ofany activated carbon particles employed. For example, the maskingparticles may have a size less than about 100 micrometers, in someembodiments less than about 50 micrometers, and in some embodiments,less than about 25 micrometers. For example, activated carbon particlesmay sometimes have a particle size of approximately 35 micrometers. Insuch cases, the size of the masking particles is typically less than 35micrometers, and preferably much smaller, such as less than about 10micrometers. Likewise, the particles may be porous. Without intending tobe limited by theory, it is believed that porous particles may provide apassage for odorous compounds to better contact the odor adsorbent. Forexample, the particles may have pores/channels with a mean diameter ofgreater than about 5 angstroms, in some embodiments greater than about20 angstroms, and in some embodiments, greater than about 50 angstroms.The surface area of such particles may also be greater than about 15square meters per gram, in some embodiments greater than about 25 squaremeters per gram, and in some embodiments, greater than about 50 squaremeters per gram. Surface area may be determined by the physical gasadsorption (B.E.T.) method of Bruanauer, Emmet, and Teller, Journal ofAmerican Chemical Society, Vol. 60, 1938, p. 309, with nitrogen as theadsorption gas.

In one particular embodiment, porous carbonate particles (e.g., calciumcarbonate) are used to alter the black color normally associated withactivated carbon. Such a color change may be more aesthetically pleasingto a user, particularly when the coating is employed on substratesdesigned for consumer/personal use. Suitable white calcium carbonateparticles are commercially available from Omya, Inc. of Proctor,Vermont. Still other suitable particles include, but are not limited to,silicates, such as calcium silicate, alumina silicates (e.g., micapowder, clay, etc.), magnesium silicates (e.g., talc), quartzite,calcium silicate fluorite, etc.; alumina; silica; and so forth. Theconcentration of the particles may generally vary depending on thenature of the particles, and the desired extent of odor control andcolor alteration. For instance, the particles may be present in the ink(prior to drying) in an amount from about 0.01 wt. % to about 30 wt. %,in some embodiments from about 0.1 wt. % to about 20 wt. %, and in someembodiments, from about 1 wt. % to about 15 wt. %.

Other compounds, such as surfactants, electrolytic salts, pH adjusters,etc., may also be included in the activated carbon ink of the presentinvention. Although not required, such additional components typicallyconstitute less than about 5 wt. %, in some embodiments less than about2 wt. %, and in some embodiments, from about 0.001 wt. % to about 1 wt.% of the activated carbon ink (prior to drying). For example, as is wellknown in the art, an electrolytic salt may be employed to control thegelation temperature of a water-soluble binder. Suitable electrolyticsalts may include, but are not limited to, alkali halides or sulfates,such as sodium chloride, potassium chloride, etc.; alkaline halides orsulfates, such as calcium chloride, magnesium chloride, etc., and soforth.

To form the activated carbon ink, its components are first typicallydissolved or dispersed in a solvent. For example, one or more of theabove-mentioned components may be mixed with a solvent, eithersequentially or simultaneously, to form an ink formulation that may beeasily applied to a substrate. Any solvent capable of dispersing ordissolving the components is suitable, for example water; alcohols suchas ethanol or methanol; dimethylformamide; dimethyl sulfoxide;hydrocarbons such as pentane, butane, heptane, hexane, toluene andxylene; ethers such as diethyl ether and tetrahydrofuran; ketones andaldehydes such as acetone and methyl ethyl ketone; acids such as aceticacid and formic acid; and halogenated solvents such as dichloromethaneand carbon tetrachloride; as well as mixtures thereof. The concentrationof solvent in the ink formulation is generally high enough to allow easyapplication, handling, etc. If the amount of solvent is too large,however, the amount of activated carbon deposited on the substrate mightbe too low to provide the desired odor reduction. Although the actualconcentration of solvent employed will generally depend on the type ofactivated carbon and the substrate on which it is applied, it isnonetheless typically present in an amount from about 40 wt. % to about99 wt. %, in some embodiments from about 50 wt. % to about 95 wt. %, andin some embodiments, from about 60 wt. % to about 90 wt. % of the ink(prior to drying).

The solids content and/or viscosity of the ink may be varied to achievethe extent of odor reduction desired. For example, the ink may have asolids content of from about 5% to about 90%, in some embodiments fromabout 10% to about 80%, and in some embodiments, from about 20% to about70%. By varying the solids content of the ink, the presence of theactivated carbon and other components in the activated carbon ink may becontrolled. For example, to form an activated carbon ink with a higherlevel of activated carbon, the ink may be provided with a relativelyhigh solids content so that a greater percentage of activated carbon isincorporated into the activated carbon ink during the applicationprocess. Generally, the viscosity is less than about 2×10⁶ centipoise,in some embodiments less than about 2×10⁵ centipoise, in someembodiments less than about 2×10⁴ centipoise, and in some embodiments,less than about 2×10³ centipoise, such as measured with a Brookfieldviscometer, type DV-I or LV-IV, at 60 rpm and 20° C. If desired,thickeners or other viscosity modifiers may be employed in the ink toincrease or decrease viscosity.

C. Ink Application

The activated carbon ink is applied to the substrate in a pattern thatpresents a stark and highly visible contrast against a different color,such as the color of the background. Thus, instead of being hiddenwithin the substrate, the activated carbon ink is used to change theoverall appearance of the substrate. For example, the activated carbonink may have a dark color (e.g., black) and applied against acontrasting light background. Alternatively, a differently coloredforeground may contrast with a dark background provided by the activatedcarbon ink. The relative degree of contrast between the odor control inkand the other color may be measured through a gray-level differencevalue. In a particular embodiment, the contrast may have a gray levelvalue of about 45 on a scale of 0 to about 255, where 0 represents“black” and 255 represents “white.” The analysis method may be made witha Quantimet 600 Image Analysis System (Leica, Inc., Cambridge, UK). Thissystem's software (QWIN Version 1.06A) enables a program to be used inthe Quantimet User Interactive Programming System (QUIPS) to make thegray-level determinations. A control or “blank” white-level may be setusing undeveloped Polaroid photographic film. An 8-bit gray-level scalemay then be used (0-255) and the program allowed the light level to beset by using the photographic film as the standard. A region containingthe other color (e.g., background or foreground) may then be measuredfor its gray-level value, followed by the same measurement of theactivate carbon ink. The routine may be programmed to automaticallycalculate the gray-level value of the activated carbon ink. Thedifference in gray-level value between the activated carbon ink and theother color may be about 45 or greater on a scale of 0-255, where 0represents “black” and 255 represents “white.”

The particular type or style of activated carbon ink pattern is not alimiting factor of the invention, and may include, for example, anyarrangement of stripes, bands, dots, or other geometric shape. Thepattern may include indicia (e.g., trademarks, text, and logos), floraldesigns, abstract designs, any configuration of artwork, etc. Thepattern may be targeted for a specific class of consumers. For example,in the case of diapers or training pants, the pattern may be in the formof cartoon characters, and so forth. It should be appreciated that the“pattern” may take on virtually any desired appearance.

Nevertheless, the activated carbon ink usually covers from about 25% toabout 95% of the surface area of the substrate, in some embodiments fromabout 30% to about 90% of the surface area of the substrate, and in someembodiments, from about 30% to about 50% of the surface area of one ormore surfaces of the substrate. Not only does such a patternedapplication have improved aesthetic appeal in comparison to uniformlyapplied inks, but the present inventors have also discovered that thepatterned ink may still achieve good odor reduction. The patternedapplication of activated carbon ink may also have various otherfunctional benefits, including optimizing flexibility, absorbency, orsome other characteristic of the substrate. The patterned application ofactivated carbon ink may also provide different odor control propertiesto multiple locations of the substrate. For example, in one embodiment,the substrate is treated with two or more regions of activated carbonink that may or may not overlap. The regions may be on the same ordifferent surfaces of the substrate. In one embodiment, one region of asubstrate is coated with a first activated carbon ink, while anotherregion is coated with a second activated carbon ink. If desired, oneregion may be configured to reduce one type of odor, while anotherregion may be configured to reduce another type of odor. Alternatively,one region may possess a higher level of an activated carbon ink thananother region or substrate to provide different levels of odorreduction.

A variety of techniques may be used for applying the activated ink inthe above-described manner. For instance, the ink may be applied usingrotogravure or gravure printing, either direct or indirect (offset).Gravure printing encompasses several well-known engraving techniques,such as mechanical engraving, acid-etch engraving, electronic engravingand ceramic laser engraving. Such printing techniques provide excellentcontrol of the composition distribution and transfer rate. Gravureprinting may provide, for example, from about 10 to about 1000 depositsper lineal inch of surface, or from about 100 to about 1,000,000deposits per square inch. Each deposit results from an individual cellon a printing roll, so that the density of the deposits corresponds tothe density of the cells. A suitable electronic engraved example for aprimary delivery zone is about 200 deposits per lineal inch of surface,or about 40,000 deposits per square inch. By providing such a largenumber of small deposits, the uniformity of the deposit distribution maybe enhanced. Also, because of the large number of small deposits appliedto the surface of the substrate, the deposits more readily resolidify onthe exposed fiber portions. Suitable gravure printing techniques arealso described in U.S. Pat. No. 6,231,719 to Garvey, et al., which isincorporated herein in its entirety by reference thereto for allpurposes. Moreover, besides gravure printing, it should be understoodthat other printing techniques, such as flexographic printing, may alsobe used to apply the coating.

Still another suitable contact printing technique that may be utilizedin the present invention is “screen printing.” Screen printing isperformed manually or photomechanically. The screens may include a silkor nylon fabric mesh with, for instance, from about 40 to about 120openings per lineal centimeter. The screen material is attached to aframe and stretched to provide a smooth surface. The stencil is appliedto the bottom side of the screen, i.e., the side in contact with thesubstrate upon which the fluidic channels are to be printed. The ink ispainted onto the screen, and transferred by rubbing the screen (which isin contact with the substrate) with a squeegee.

Ink-jet printing techniques may also be employed in the presentinvention. Ink-jet printing is a non-contact printing technique thatinvolves forcing the ink through a tiny nozzle (or a series of nozzles)to form droplets that are directed toward the substrate. Two techniquesare generally utilized, i.e., “DOD” (Drop-On-Demand) or “continuous”ink-jet printing. In continuous systems, ink is emitted in a continuousstream under pressure through at least one orifice or nozzle. The streamis perturbed by a pressurization actuator to break the stream intodroplets at a fixed distance from the orifice. DOD systems, on the otherhand, use a pressurization actuator at each orifice to break the inkinto droplets. The pressurization actuator in each system may be apiezoelectric crystal, an acoustic device, a thermal device, etc. Theselection of the type of ink jet system varies on the type of materialto be printed from the print head. For example, conductive materials aresometimes required for continuous systems because the droplets aredeflected electrostatically. Thus, when the sample channel is formedfrom a dielectric material, DOD printing techniques may be moredesirable.

In addition to the printing techniques mentioned above, any othersuitable application technique may be used in the present invention. Forexample, other suitable printing techniques may include, but not limitedto, such as laser printing, thermal ribbon printing, piston printing,spray printing, flexographic printing, etc. Still other suitableapplication techniques may include bar, roll, knife, curtain, spray,slot-die, dip-coating, drop-coating, extrusion, stencil application,etc. Such techniques are well known to those skilled in the art.

Regardless of the method of application, the odor control substrate maysometimes be dried at a certain temperature to drive the solvent fromthe activated carbon ink. For example, the substrate may be heated to atemperature of at least about 50° C., in some embodiments at least about70° C., and in some embodiments, at least about 80° C. By minimizing theamount of solvent in the activated carbon ink, a larger surface area ofactivated carbon may be available for contacting odorous compounds,thereby enhancing odor reduction. It should be understood, however, thatrelatively small amounts of solvent may still be present. For example,the dried ink may contain a solvent in an amount less than about 10% byweight, in some embodiments less than about 5% by weight, and in someembodiments, less than about 1% by weight.

When dried, the relative percentages and solids add-on level of theresulting activated carbon coating may vary to achieve the desired levelof odor control. The “solids add-on level” is determined by subtractingthe weight of the untreated substrate from the weight of the treatedsubstrate (after drying), dividing this calculated weight by the weightof the untreated substrate, and then multiplying by 100%. One particularbenefit of the present invention is that high solids add-on levels andactivated carbon levels are achievable without a substantial sacrificein durability of the coating. In some embodiments, for example, theadd-on level of the activated carbon ink is at least about 2%, in someembodiments from about 4% to about 40%, and in some embodiments, fromabout 6% to about 35%. Further, the coating may contain from about 10wt. % to about 80 wt. %, in some embodiments from about 20 wt. % fromabout 70 wt. %, and in some embodiments, from about 40 wt. % to about 60wt. % of activated carbon. Likewise, the coating may also contain fromabout 10 wt. % to about 80 wt. %, in some embodiments from about 10 wt.% from about 60 wt. %, and in some embodiments, from about 30 wt. % toabout 50 wt. % of binder.

D. Additional Inks

To further improve the aesthetic appeal of the odor control substrate,one or more additional inks may also be employed that contrast with thecolor of the activated carbon ink (e.g., black). Possible colors thatcontrast well with a black ink include, for instance, white, yellow,cyan, magenta, red, green, blue, etc. However, any ink may generally beemployed so long as some perceivable difference exists between thecolors of the inks. To provide the desired color, the colored ink mayinclude a colorant, such as a pigment, dye, etc. The colorant mayconstitute from about 0.01 to about 20 wt. %, in some embodiments fromabout 0.1 wt. % to about 10 wt. %, and in some embodiments, from about0.5 wt. % to about 5 wt. % of the colored ink. For example, the colorantmay be an inorganic and/or organic pigment. Some examples ofcommercially available organic pigments that may be used in the presentinvention include those that are available from Clariant Corp. ofCharlotte, N.C., under the trade designations GRAPHTOL® or CARTAREN®.Other pigments, such as lake compounds (blue lake, red lake, yellowlake, etc.), may also be employed. Inorganic and/or organic dyes mayalso be utilized as a colorant. Exemplary organic dye classes includetriarylmethyl dyes, monoazo dyes, thiazine dyes, oxazine dyes,naphthalimide dyes, azine dyes, cyanine dyes, indigo dyes, coumarindyes, benzimidazole dyes, paraquinoidal dyes, fluorescein dyes,diazonium salt dyes, azoic diazo dyes, phenylenediamine dyes, diazodyes, anthraquinone dyes, trisazo dyes, xanthene dyes, proflavine dyes,sulfonaphthalein dyes, phthalocyanine dyes, carotenoid dyes, carminicacid dyes, azure dyes, acridine dyes, and so forth. One particularlysuitable class of dyes includes anthraquinone compounds, which may beclassified for identification by their Color Index (CI) number. Forinstance, some suitable anthraquinones that may be used in the presentinvention, as classified by their “CI” number, include Acid Black 48,Acid Blue 25 (D&C Green No. 5), Acid Blue 40, Acid Blue 41, Acid Blue45, Acid Blue 129, Acid Green 25, Acid Green 27, Acid Green 41, MordantRed 11 (Alizarin), Mordant Black 13 (Alizarin Blue Black B), Mordant Red3 (Alizarin Red S), Mordant Violet 5 (Alizarin Violet 3R), Natural Red 4(Carminic Acid), Disperse Blue 1, Disperse Blue 3, Disperse Blue 14,Natural Red 16 (Purpurin), Natural Red 8, Reactive Blue 2, and so forth.

Besides a colorant, the ink may also include various other components asis well known in the art, such as colorant stabilizers, photoinitiators,binders, solvents, surfactants, humectants, biocides or biostats,electrolytic salts, pH adjusters, etc. For example, various componentsfor use in an ink are described in U.S. Pat. No. 5,681,380 to Nohr, etal. and U.S. Pat. No. 6,542,379 to Nohr, et al., which are incorporatedherein in their entirety by reference thereto for all purposes. Suchinks typically contain water as a principal solvent, and particularlydeionized water in an amount from about 20 wt. % to about 95 wt. % ofthe ink. Various co-solvents may also be included in the inkformulation. Examples of such co-solvents include a lactam, such asN-methyl pyrrolidone. Other examples of optional co-solvents includeN-methylacetamide, N-methylmorpholine-N-oxide, N,N-dimethylacetamide,N-methyl formamide, propyleneglycol-monomethylether, tetramethylenesulfone, and tripropyleneglycolmonomethylether. Still other co-solventsthat may be used include propylene glycol and triethanolamine (TEA). Ifan acetamide-based co-solvent is included in the formulation, it istypically present within a range of from about 1 to about 12 wt. %.

Humectants may also be utilized, such as in an amount between about 0.5and 20 wt. % of the ink. Examples of such humectants include, but arenot limited to, ethylene glycol; diethylene glycol; glycerine;polyethylene glycol 200, 400, and 600; propane 1,3 diol;propylene-glycolmonomethyl ethers, such as Dowanol PM (Gallade ChemicalInc., Santa Ana, Calif.); polyhydric alcohols; or combinations thereof.Other additives may also be included to improve ink performance, such asa chelating agent to sequester metal ions that could become involved inchemical reactions over time, a corrosion inhibitor to help protectmetal components of the printer or ink delivery system, a biocide orbiostat to control unwanted bacterial, fungal, or yeast growth in theink, and a surfactant to adjust the ink surface tension. If a surfactantis included, it is typically present in an amount of between about 0.1to about 1.0 wt. %. If a corrosion inhibitor is included, it istypically present in an amount between about 0.1 and about 1.0 wt. %. Ifa biocide or biostat is included, it is typically present in an amountbetween about 0.1 and about 0.5 wt. %.

The colored inks may be formed by any known process. For instance, onesuch process involves mixing all of the components together, heating themixture to a temperature of from about 40° C. to about 55° C. for aperiod of from about 2 to about 3 hours, cooling the mixture to roomtemperature (typically from about 10° C. to about 35° C.), and filteringthe mixture to obtain an ink. The viscosity of the resulting ink istypically is no more than about 5 centipoise, and in some embodimentsfrom about 1 to about 2.5 centipoise.

The process for forming a patterned substrate having an activated carbonink and an additional ink may involve sequentially applying the inksonto one or more surfaces of the substrate. The colored ink may beapplied to the same surface as the activated carbon ink so that areadily visible pattern is achieved. Alternatively, the activated carbonink and colored ink may be applied on opposing surfaces so that thecolored ink acts as a contrasting background for the activated carbonink. The colored ink may generally be applied using any known method,such as those referred to above. The colored ink may be uniformlyapplied to the substrate surface, or applied in a pattern that coversless than 100% of the area of the surface.

When utilized, the colored and activated carbon inks may be applied inan overlapping or non-overlapping relationship. Referring to FIG. 1A,for instance, one embodiment of a patterned substrate 10 is shown inwhich an ink 12 is printed on top of an activated carbon ink 14 in anoverlapping relationship. FIG. 1B illustrates an alternative embodimentin which the activated carbon ink 14 is printed on top of the ink 12. Ineither case, the top ink generally does not cover the entire surfacearea of the bottom ink. This is to ensure that the activated carbon inkis able to contact and adsorb odorous compounds, and that a clearpattern is observed. For example, the top ink may cover less than about90%, in some embodiments less than about 75%, and in some embodiments,less than about 50% of the surface area of the bottom ink.

On the other hand, referring to FIG. 2, another substrate 100 is shownthat includes an ink 112 and an activated carbon ink 114 applied in anon-overlapping relationship. Such a non-overlapping relationship mayprovide a variety of benefits to the resulting odor control substrate100. For example, in certain cases, the activated carbon ink 114 mighthave an adverse affect on the flexibility, absorbency, and/or some othercharacteristic of the substrate 100. By minimizing the area to which theactivated carbon ink 114 is applied, any such adverse affect isminimized. In addition, a non-overlapping relationship may also providea clearer definition of the pattern provided by the inks.

E. Articles

The patterned odor control substrate of the present invention may beemployed in a wide range of articles. In one particular embodiment, thepatterned odor control substrate is used to form a pouch for anabsorbent article. Specifically, many absorbent articles (e.g., femininehygiene products) are disposed by placing them in a small pouch in whichthe product is packaged for sale. Thus, the odor control substrate ofthe present invention may be employed in the pouch to help reduce odorsassociated with the dispensed absorbent articles. Referring to FIGS.3-4, for example, one embodiment of an individually wrapped absorbentarticle package 50 is illustrated. As shown, an absorbent article 42 iscarried in the package 50, which for purposes of description only, isshown as a feminine care product (e.g., sanitary pad or napkin). Theabsorbent article 42 may be folded in any desired pattern to fit in thepackage 50.

The package 50 includes an elongate piece of wrapper 44 that is foldedand bonded into the desired pouch configuration. For example, thewrapper 44 may be an elongated rectangular piece having a first end 26,an opposite second end 28, and generally parallel longitudinal sides 33and 35 extending between the ends 26 and 28. Various other pouchconfigurations are known and used in the art for individually packagingfeminine care absorbent articles and any such configuration may be usedin a package according to the invention. For example, various otherpouch configurations are disclosed in U.S. Pat. No. 6,716,203 to Sorebo,et al. and U.S. Pat. No. 6,380,445 to Moder, et al., as well as U.S.Patent Application Publication No. 2003/0116462 to Sorebo, et al., allof which are incorporated herein in their entirety by reference theretofor all purposes. In the illustrated embodiment, for example, a pouch 40is shown that is similar to the pouch configuration used for Kotex®Ultrathin pads available from Kimberly-Clark Corporation.

The wrapper 44 is essentially folded around the absorbent article 42such that the pouch 40 is formed around the article. The wrapper 44 isfirst folded at a first fold axis 30 such that the first end 26 isfolded towards but spaced from the second end 28. The distance betweenthe first end 26 and second end 28 may vary depending on the desiredlength of a resulting flap 20, as described below. The alignedlongitudinal sides of the wrapper 44 define sides 34 and 36 of the pouch40. The second end 28 of the wrapper 44 is then folded at a second foldaxis 32 so as to extend back over the first end 26 and thus defines theflap 20 that closes off the pouch 40. The flap 20 has longitudinal sides24 and 22 that align with the material sides 33 and 35 and pouch sides34 and 36. The sides of the pouch 40 are then bonded in a conventionalmanner, for example with a heat/pressure embossing roll. The flap sides22 and 24 are bonded to the material sides 33 and 35 and pouch sides 34and 36 in a single pass operation. It may be the case that the first end26 of the wrapper 44 extends essentially to the second fold axis 32 and,thus, the flap sides 22 and 24 would be bonded along their entire lengthto pouch sides 34 and 36. The edge of the second end 28 may extendacross the front surface of the pouch 40. It may be desired to adhereall or a portion of this edge to the pouch surface. However, in adesirable embodiment, this edge is left un-adhered to the pouch betweenits bonded sides 22 and 24.

Regardless of the particular pouch configuration, the wrapper 44 may beformed from a variety of different materials, including a film, afibrous material (e.g., nonwoven web), and combinations thereof. Forexample, the wrapper 44 may sometimes contain a breathable film. In oneparticular embodiment, the odor control substrate of the presentinvention is used to form one or materials of the wrapper 44. Typically,when utilized in this manner, it is desired that the pattern of inks isvisible to the user and also capable of adsorbing odorous compounds. Forexample, as shown, a pattern 80 of an activated carbon ink 84 is appliedover a colored ink 82. In this particular embodiment, the inks 82 and 84are present on an inner surface 61 of the wrapper 44 so that they aremore readily able to contact odorous compounds stemming from theabsorbent article 42. Alternatively, however, the inks 82 and/or 84 mayalso be present on other surfaces of the wrapper 44, such as an outersurface 63.

Besides being used in a pouch configuration, the substrate may also beused in one or more components of an absorbent article, such as in aliquid-permeable layer (e.g., bodyside liner, surge layer, etc.),liquid-impermeable or breathable layer (e.g., outer cover, ventilationlayer, baffle, etc.), absorbent core, elastic member, and so forth.Several examples of such absorbent articles are described in U.S. Pat.No. 5,197,959 to Buell; U.S. Pat. No. 5,085,654 to Buell; U.S. Pat. No.5,634,916 to Lavon, et al.; U.S. Pat. No. 5,569,234 to Buell, et al.;U.S. Pat. No. 5,716,349 to Taylor, et al.; U.S. Pat. No. 4,950,264 toOsborn, III; U.S. Pat. No. 5,009,653 to Osborn, III; U.S. Pat. No.5,509,914 to Osborn, III; U.S. Pat. No. 5,649,916 to DiPalma, et al.;U.S. Pat. No. 5,267,992 to Van Tillburg; U.S. Pat. No. 4,687,478 to VanTillburg; U.S. Pat. No. 4,285,343 to McNair; U.S. Pat. No. 4,608,047 toMattingly; U.S. Pat. No. 5,342,342 to Kitaoka; U.S. Pat. No. 5,190,563to Herron, et al.; U.S. Pat. No. 5,702,378 to Widlund, et al.; U.S. Pat.No. 5,308,346 to Sneller, et al.; U.S. Pat. No. 6,110,158 toKielpikowski; U.S. Pat. No. 6,663,611 to Blaney, et al.; and WO 99/00093to Patterson, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

The odor control substrate of the present invention is versatile and mayalso be used with other types of articles of manufacture. For instance,the odor control substrate may be used in air filters, such as housefilters, vent filters, disposable facemasks, and facemask filters.Exemplary facemasks, for instance, are described and shown, for example,in U.S. Pat. Nos. 4,802,473; 4,969,457; 5,322,061; 5,383,450; 5,553,608;5,020,533; 5,813,398; and 6,427,693, which are incorporated herein intheir entirety by reference thereto for all purposes. In one embodiment,the odor control substrate of the present invention may be utilized as afiltration layer of the facemask. Filtration layers, such as meltblownnonwoven webs, spunbond nonwoven webs, and laminates thereof, are wellknown in the art.

In still other embodiments, the odor control substrate may be employedin conjunction with a garment. For instance, garments, such as meat andseafood packing industry aprons/attire, grocery store aprons, paper millaprons/attire, farm/dairy garments, hunting garments, etc., may beincorporated with the odor control substrate of the present invention.As an example, hunters often wear garments that are camouflaged for theparticular hunting environment. The odor control substrate of thepresent invention may thus be used to form the patterned camouflagepattern. Specifically, the odor control substrate may impart the desiredcolor pattern and also help reduce human odor during hunting. Inaddition, the odor control coating may be employed on a cover for petbeds, chairs, elder care/hospital bed covers, infant/children cribs, andso forth.

The effectiveness of the odor control substrate of the present inventionin reducing odor may be measured in a variety of ways. For example, thepercent of an odorous compound adsorbed by the odor control substratemay be determined using the headspace gas chromatography test as setforth herein. In some embodiments, for instance, the odor controlsubstrate of the present invention is capable of adsorbing at leastabout 25%, in some embodiments at least about 45%, and in someembodiments, at least about 65% of a particular odorous compound. Theeffectiveness of the activated carbon ink in removing odors may also bemeasured in terms of “Relative Adsorption Efficiency”, which is alsodetermined using headspace gas chromatography and measured in terms ofmilligrams of odor adsorbed per gram of the activated carbon ink. Itshould be recognized that the surface chemistry of any one type ofactivated carbon ink may not be suitable to reduce all types of odors,and that low adsorption of one or more odorous compounds may becompensated by good adsorption of other odorous compounds.

The present invention may be better understood with reference to thefollowing examples.

Test Methods

Quantitative odor adsorption was determined in the Examples using a testknown as “Headspace Gas Chromatography.” Headspace gas chromatographytesting was conducted on an Agilent Technologies 5890, Series II gaschromatograph with an Agilent Technology 7694 headspace sampler (AgilentTechnologies, Waldbronn, Germany). Helium was used as the carrier gas(injection port pressure: 12.7 psig; headspace vial pressure: 15.8 psig;supply line pressure is at 60 psig). A DB-624 column was used for theodorous compound that had a length of 30 meters and an internal diameterof 0.25 millimeters. Such a column is available from J&W Scientific,Inc. of Folsom, Calif.

The operating parameters used for the headspace gas chromatography areshown below in Table 1: TABLE 1 Operating Parameters for the HeadspaceGas Chromatography Device. Headspace Parameters Zone Temps, ° C. Oven 37Loop 85 TR. Line 90 Event Time, minutes GC Cycle time 10.0 Vial eq. Time10.0 Pressuriz. Time 0.20 Loop fill time 0.20 Loop eq. Time 0.15 Injecttime 0.30 Vial Parameters First vial 1 Last vial 1 Shake [off]

The test procedure involved placing 0.005 to 0.1 grams of a sample in a20 cubic centimeter (cc) headspace vial. Using a syringe, an aliquot ofan odorous compound was also placed in the vial. Specifically, testingwas done with 2.0 micrograms of ethyl mercaptan (2.4 microliters) and1.8 micrograms (2 microliters) of dimethyldisulfide. The samples weretested in triplicate. After ten minutes, a hollow needle was insertedthrough the septum and into the vial. A 1-cubic centimeter sample of theheadspace (air inside the vial) was then injected into the gaschromatograph. Initially, a control vial with only the aliquot ofodorous compound was tested to define 0% odorous compound adsorption. Tocalculate the amount of headspace odorous compound removed by thesample, the peak area for the odorous compound from the vial with thesample was compared to the peak area from the odorous compound controlvial.

EXAMPLE 1

The ability to apply activated carbon ink to a substrate wasdemonstrated. The activated carbon ink was obtained from MeadWestvacoCorp. under the name “Nuchar PMA”, and contained 15 wt. % activatedcarbon, 12 wt. % styrene-acrylic copolymer binder, and 73 wt. % water.Flat steel rolls were used in a standard off-set gravure printing system(obtained from Faustel Inc. of Germantown, Wis.) to uniformly print theactivated carbon ink onto one side of the polyethylene film. The filmhad a basis weight of 27.1 grams per square meter, and had beenpreviously exposed to a corona discharge treatment as is well known theart. After printing, the films were dried with a through-air dryer at atemperature of 190° F. for approximately 5 seconds. Seven (7) differentsamples were printed with the activated carbon ink in theabove-described manner, each having varying coating weights and printpatterns. The line speeds and coating wheigths also calculated as solidsadd-on level) used for the activated carbon samples are set forth belowin Table 2. TABLE 2 Activated Carbon Samples Line Speed for PrintingCoating Weight Solids Add-On Level Sample (ft/min) (gsm) (%) Control — —— 1 100 8.5 31.4 2 100 2.8 10.3 3 100 2.8 10.3 4 100 3.5 12.9 5 100 0.62.2 6 1000 4.3 15.9 7 1000 4.3 15.9

Several of the samples were then tested for their ability to removeethyl mercaptan and dimethylsulfide odorous compounds using theheadspace gas chromatography test described above. The results are setforth below in Table 3. TABLE 3 Odor Reduction Ethyl MercaptanDimethyldisulfide Sample (% removed) (% removed) 1 66.0 61.5 2 45.0 71.84 56.0 71.4 5 35.9 55.9

The above odor reduction data was then employed to obtain a correlationbetween coating weight and the percent coverage (i.e., print pattern).The study measured the odor adsorption capacity for different sampleareas having the same coating weight. In other words, different samplesizes were cut out from the same coated film, and the odor capacity wasthen measured. This was repeated for all the films having differentcoating weights. Referring to FIG. 5, a graph is depicted of theresulting odor adsorption isotherms for each coating. From this graph,one may determine the coating weight (or solids add-on level) requiredfor a desired print area and odor capacity. Alternatively, one may alsodetermine the print area required for a desired coating weight (orsolids add-on level) and odor capacity.

EXAMPLE 2

The ability to apply activated carbon ink to a substrate in a certainpattern was demonstrated. The activated carbon ink was obtained fromMeadWestvaco Corp. under the name “Nuchar PMA”, and contained 15 wt. %activated carbon, 12 wt. % styrene-acrylic copolymer binder, and 73 wt.% water. Gravure steel rolls were used in a standard off-set gravureprinting system (obtained from Faustel Inc. of Germantown, Wis.) toprint the activated carbon ink onto one side of the polyethylene film.The film had a basis weight of 27.1 grams per square meter, and had beenpreviously exposed to a corona discharge treatment as is well known inthe art. After printing, the films were dried with a through-air dryerat a temperature of 190° F. for approximately 5 seconds.

The activated carbon ink was printed in a floral pattern on the film atvarious coating weights (or solids add-on levels) and patterns. Severalof the samples were then tested for their ability to remove ethylmercaptan odorous compounds using the headspace gas chromatographydevice described above. The results are set forth below in Table 4.TABLE 4 Activated Carbon Samples Line Coating Ethyl Speed Weight SolidsAdd- Surface Area Mercaptan Sample (ft/min) (gsm) On Level (%) Covered(%) (% removed) 8 100 6 22.1 25 20 9 100 6 22.1 75 58 10 100 4 14.8 2516 11 100 4 14.8 75 50

While the invention has been described in detail with respect to thespecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing, mayreadily conceive of alterations to, variations of, and equivalents tothese embodiments. Accordingly, the scope of the present inventionshould be assessed as that of the appended claims and any equivalentsthereto.

1. A method for forming an odor control substrate, said methodcomprising: forming a first ink that comprises activated carbon, abinder, and a solvent; printing said first ink onto a surface of saidsubstrate, wherein said first ink covers from about 25% to about 95% ofthe area of said surface, and wherein said first ink presents a colorthat is visually distinguishable from another color presented by saidsubstrate; and drying said first ink so that the solids add-on level isat least about 2%.
 2. The method of claim 1, wherein said substratecontains a nonwoven web, a film, or combination thereof.
 3. The methodof claim 1, wherein said activated carbon comprises from about 1 wt. %to about 50 wt. % of said first ink.
 4. The method of claim 1, whereinsaid binder comprises from about 0.01 to about 30 wt. % of said firstink.
 5. The method of claim 1, wherein said solvent comprises from about40 wt. % to about 99 wt. % of said first ink.
 6. The method of claim 1,wherein said first ink covers from about 30% to about 90% of the area ofsaid surface.
 7. The method of claim 1, wherein the solids add-on levelof said first ink is from about 4% to about 40%.
 8. The method of claim1, wherein the contrast between the color of said first ink and anothercolor presented by the substrate has a minimum gray scale value of atleast about 45 on a scale of 0-255.
 9. The method of claim 1, whereinthe color of said first ink is black.
 10. The method of claim 1, furthercomprising printing a second ink onto said substrate that presents acolor that is visually distinguishable from the color of said first ink.11. The method of claim 10, wherein the color of said second ink iswhite, yellow, cyan, magenta, red, green, blue, or a combinationthereof.
 12. The method of claim 10, wherein said first and second inksare applied in an overlapping relationship.
 13. The method of claim 10,wherein said first and second inks are applied in a non-overlappingrelationship.
 14. An odor control substrate that is applied with a firstink and a second ink, said first ink comprising activated carbon, saidfirst ink covering from about 30% to about 90% of the area of a surfaceof the substrate and being present at a solids add-on level of at leastabout 2%, wherein said first ink presents a color that is visuallydistinguishable from the color of said second ink.
 15. The odor controlsubstrate of claim 14, wherein said substrate contains a nonwoven web, afilm, or combination thereof.
 16. The odor control substrate of claim14, wherein the contrast between said first ink and said second ink hasa minimum gray scale value of at least about 45 on a scale of 0-255. 17.The odor control substrate of claim 14, wherein the color of said firstink is black.
 18. The odor control substrate of claim 14, wherein thesolids add-on level of said first ink is from about 4% to about 40%. 19.The odor control substrate of claim 14, wherein said first and secondinks are applied in an overlapping relationship.
 20. The odor controlsubstrate of claim 14, wherein said first and second inks are applied ina non-overlapping relationship.
 21. A pouch for an absorbent article,the pouch comprising the substrate of claim
 14. 22. A pouch forindividually wrapping a feminine care absorbent article, the pouchcomprising a wrapper having an inner surface, wherein said inner surfaceis applied with a first ink that comprises activated carbon, said firstink covering from about 25% to about 95% of the area of said innersurface, wherein said first ink presents a color that is visuallydistinguishable from another color presented by said wrapper.
 23. Thepouch of claim 22, wherein said wrapper contains a film that definessaid inner surface.
 24. The pouch of claim 22, wherein the contrastbetween said first ink and another color presented by said wrapper has aminimum gray scale value of at least about 45 on a scale of 0-255. 25.The pouch of claim 22, wherein the color of said first ink is black. 26.The pouch of claim 22, wherein a second ink is also present on saidinner surface of said wrapper, said second ink presenting a color thatis visually distinguishable from the color of said first ink.
 27. Thepouch of claim 26, wherein said first and second inks are applied in anoverlapping relationship.
 28. The pouch of claim 26, wherein said firstand second inks are applied in a non-overlapping relationship.
 29. Thepouch of claim 22, wherein the solids add-on level of said first ink isat least about 2%.